Dynamics of the inner electron radiation belt: A review

The Van Allen radiation belts are an extraordinary science discovery in the Earth magnetosphere and consist of two electron belts. The inner Van Allen belt contains electrons of 10s to 100s keV; the outer belt consists mainly of 0.1−10 MeV electrons. Their dynamics have been analyzed for decades. The newly-launched Van Allen Probes provide unprecedented opportunities to investigate the inner belt more thoroughly. Data from this advanced mission have allowed scientists to demonstrate that the inner belt was formed not only through inward transport of outer belt electrons but Cosmic Ray Albedo Neutron Decay (CRAND) has also played an important role. In addition, the inner belt electrons show energy-dependent variations and present “zebra stripe” structures in the energy spectrum. At the same time, scientists have further confirmed that the electrons in the inner radiation belt get lost through coulomb collision and wave-particle interaction. Despite these advances, important questions remain unanswered and require further investigation. The launch of Macau ScienceSatellite-1 mission, with its low inclination angle and low altitude orbit, will provide advanced radiation belt data for better understanding of the structure and dynamics of the inner electron radiation belt.